The present invention relates to seals, gaskets and the like, and more particularly to a multi-level seal or gasket to retain or seal toner in a printer cartridge or the like.
Sealing subassemblies with multiple interfacing surfaces that are at different elevations, levels or topologies can be challenging. This problem can be exacerbated when the multiple elevations or levels are concentric and require proper alignment and cooperation to form efficient seals. One example of sealing multiple surfaces with differing levels and topologies is a printer cartridge. The seal must prevent leakage of toner and not interfere with proper operation of internal components of the cartridge. Difficulty in sealing a cartridge increases when multiple contoured surfaces and geometries are introduced at different levels between components or subassemblies, such as a magnetic or mag roller subassembly and a tone hopper subassembly. In some cartridges, the toner low sensing mechanism may obstruct the seal from lying flat against the sealing surface of the magnetic roller subassembly. Multiple plane geometries in the sealing interface areas or surfaces can produce voids prohibiting the seal from sealing properly. On the toner hopper assembly, changing topologies or levels between upper and lower sealing surfaces also increases sealing difficulty. The height difference between the two surfaces is important because the toner low sensing mechanism must be positioned between the upper and lower sealing surfaces of the hopper subassembly after final assembly of the two subassemblies. The presence of a seal or portion of the seal between the toner low sensing mechanism and the toner could interfere with a proper toner low indication. Additionally, the seal should not over hang or extend over a lower sealing surface and partially protrude into the toner hopper because toner may become trapped underneath the seal. Trapping some toner could reduce the number of pages printable by restricting the toner from being introduced to the magnetic roller. Further, sealing problems may occur when exit geometries from the lower sealing surface to the outside of the cartridge produce leak paths.